Reliability and validity of visual observation when classifying spinal deformities in adolescents with idiopathic scoliosis based on the Schroth Classification: a retrospective cross-sectional study

Background/Aims Classification for scoliosis is of significant importance for clinicians to organise the therapy plan and to decide the appropriate treatment. The aim of this study was to investigate the validity and reliability of the Schroth Classification using visual observation only, as this is an equally important part that guides therapists in their final decisions for conservative treatment in scoliosis. Methods Three therapists certified in the Schroth Method evaluated the accuracy and reliability of this classification system. They studied photographs of 68 patients with idiopathic scoliosis. For validity testing, the choices of the three therapists were compared with the classification according to the Schroth Method, which the independent investigator, a certified instructor of the method, had concluded after examining the patients, which included all relevant tests, observations, Schroth flexibility tests and X-ray radiographs. Reliability was measured using Kappa value to evaluate intra-examiner and inter-examiner level of agreement Results Concerning the validity with the use of Kappa value, the most experienced examiner (Examiner A) had k=0.68 regarding the Schroth Classification, Examiner B had k=0.45 and Examiner C had k=0.38. Test–retest reliability was good to substantial for the three examiners with Kappa value ranging from 0.74 to 0.94. The experienced examiner showed the highest level of agreement. Inter-examiner reliability was lower with Kappa values ranging from 0.24 to 0.85 Conclusions The Schroth Classification is reliable for classifying patients with scoliosis when used by experienced qualified assessors. Although it is always wise to gain an image of the X-ray to confirm both the diagnosis and the pattern, the Schroth Classification appears to be reliable in situations where there is no access to X-rays and classification is performed by visual observation only. Implications for practice The findings of the study indicate that experienced and properly trained therapists have the capability to accurately classify scoliosis solely through visual observation. This observation bears significant practical implications for clinical settings where radiographic imaging is unavailable, thereby enabling clinicians to make decisions concerning Schroth therapy strategies and initiate appropriate treatment. Radiographic imaging and the Schroth flexibility tests remain indispensable and critical instruments for conducting a comprehensive and secure evaluation. Additional training may be requisite for less experienced therapists to enhance the precision of classification.